Viral marketing is often presented as the Holy Grail of marketing. The story goes something like this: create a clever/funny low-budget video, whack it up on YouTube and watch the hits roll in as people send the link to friends who themselves forward it on in turn. The numbers are certainly seductive, YouTube's all time most viewed video has to date racked up over 82m views.
Of course, most of these are either unintentionally viral or music videos. Once we're into commercial efforts, the numbers drop significantly (but are still pretty high). Take the excellent Will it Blend? series. The top viewed video – blending an iPod – has had over 5m views. Most efforts, however, score in the thousands rather than millions. And many more produce efforts that have nothing whatsoever to do with either their product or brand.
In many ways, it's a shame that viral has come to mean video (or at a stretch, video + games). This has constrained the thinking of many companies, restricting their options and harming their results.
The latest crop of Change This manifestos could help. It includes the wonderfully named, Word of mouse by David Meerman Scott. While in some ways it presents nothing staggeringly new, it does give a good overview of viral that goes beyond YouTube to encompass ebooks, "secret" microsites and branded utilities (plus the obligatory bit on video as well). It's well worth a read.